In a conventional multi-stage oil buffer, a first cylinder is inserted into a base cylinder. A second cylinder having a smaller diameter than that of the first cylinder is inserted into the first cylinder. A third cylinder having a smaller diameter than that of the second cylinder is inserted into the second cylinder. A return spring is provided between the base cylinder and the first cylinder. A hydraulic oil is enclosed in the first and second cylinders (for example, see Patent Document 1).    Patent Document 1: JP 04-217577 A